Diamond tool and method for making the same



Oct. 26, 1948. e. w. LUCAS DIAMOND TOOL AND METHOD FOR MAKING THE SAME Filed May 10, 1944 Inventor:

George W. Luas,

r HIS Attorney Patented Oct. 26, 1948 DIAMOND 1c ANDMEIHODFOR- THE George W. Lucas, :Sft.fiClair Shores, .'Mich.,:ass'ign'ortD Carboloy-"Gompany, Inc.,.l.a corporation :of

New Kori;

"The presentinvention is :a' diamondtool and more particularly a diamond 'tru-ingtodl "for :use

in dressing grinding wheels making the-same.-

Itis'one of the objects c'fthepresentinvention to provide adi-amond 'tool'in which injury to the diamonds during setting is-"avoided; further object is to provide-a setting in which the diamonds are held rigidly in position; a further object is to obtain a uniform distribution of the diamonds in the tool, another-is to provide a diamond tool in which rigid control of the quality of the-diamond'todlis obtained; a' further object is to provide a diamond "tool-adapted for mass production.

"The-novelf-eatm'es which-*are characteristic of my invention areset'fforthwithparticularity in the "appended claims; It [y invention itself however will best be nnderstoodiromreference to the following specification "when considered in connection with the accompanying-drawing in which Fig. 1 is a vertical cross sectional view of a-steel mold employedin carrying .outmy invention; Fig. 2 is a vertical cross sectional view, on an enlarged scale, of the bottom plunger employed in my'process; Fig. 3 is-a plan "view 'of the bottom plunger illustrated in Fig. 2; Fig; '4 is a view in elevation :of the top plunger employed in my process; Figse5 and-6 are respectively a plan'vi'ew and-a vertical sectional-view both on anenlarge'd scale, or the loading plunger; Figs. 7 and 8 are respectively a plan view and a vertical elevation, both on an-enlarged scale, of a ta-pping rod which fits with-in vthe opening -2 in-the steel mold; Figs. 9 and f-lO aretertical,elevational-views of press rods adaptedrespectivelygfor'use with the central opening and the radially positioned openings in the loadingplunger; while-Fig. I1 is a crossse'ctional view of a graphite \containeriwithsa pressed diamond tool in position to be sintered andimr ema at --Referring more particularly to: the ,rdrawing, Ihave'indicated at 'l a'steel'mold having :a round opening extending'therethrough, the upper-half 2 of the openingpomprising 'a'stra'ight cylindrical opening, while the lower half 3 is slightly tapered. A steel bottom plunger 4 having a tapered surface is adapted to fit snugly in the conical or tapered opening 3 in the steel mold I. The top or upper concave surface of the plunger 4 has a plurality of conical shaped cavities thereon comprising a central cavity 5 and a series of cavities 6 which are spaced circumferentially and substantially equal distances apart, the centers of all cavities 6 being located on a circle the center of which is in and -a method for a line constituting an "eXlIeiISiOH- of theaxisiof the bottom plunger-"4; "Whenseven cavities are =emplayed an angle of 'albout is formedby'two straight lines passingrespectively through the centers of adjacent cavities 6 and intersecting at the centerof 'the central cavity 5.

In carrying out my improved process; a on mend, which may be a whole 'diamondorga-chip, is positioned in each of the openings -5 and'li on plunger tandcovered with hard metal powder which preferahlyconsists'of any one'or morehardmetal carbides, for example tungsten carbide; molybdenum carbide, titanium carbide, tantalum: carbide, such as generallyemployed in the manu-- facture of cemented carbide compositions. If

desired, a small quantity of copper and-cobalt.

maybe added to the carbide, for exampleoneaddition of such'elements ,is not essential, they impart toughness to thepressed'diamondimpregnated article and permit t to :be ha dledg'sarely prior t the nte i ope t o The powdered. carbide may be pressed over the diamonds intheopenings 5 andfi Icy-hand. after which the plunger ,4 is inserted .in t e. tapered Opening-3 of the mold .l AKtap-ping rodll havin g. a ,dome shapedlower end 8 then is inserted .in ,the opening v2 or the mold i and pressed intothe powderedmaterial thereby forming an upper surface :thereonsimilar to and having substan--- tially the same concavity as the uppersurface of the plunger =4. Tapping .rod fl is now withdrawn and (a loading plunger "9 inserted in its -placegin the opening 2 of the steelmold. Theloadingi.

plunger 'is provided with a central longitudinal oraxial opening l ll and six parallel openings H which are :spaced apart substantially identically with the cavities 'iiand .B-on" the bottom plungerzfle 'Ehe'loading plunger *9 has a .dome shaped lowerend lizxisubstantially identical .in shape andrextent withtherdome shaped endportion'8 of the tappingi rod 1. After the loading plunger-Shesbeen-positioned in the openin'giZ in the mold I 'a diamond is deposited in each of theopeningsl-lland H and pressed into the carbide powder by press rods 13 and M the reduced ends of which are inserted and -fit respectively in the openings 10 and I I of the loading plunger 9. Press rods l3 and I4 have enlarged upper end portions l5 and I6 respectively which are adapted to contact with the upper surface of the loading plunger 9 and limit the movement of the press rod therein. The reduced portion of press rod l3 has the same length as the central opening It] in the loading plunger 3 What I claim as new and desire to secure by Letters Patent of the United States, is:

1. A diamond tool comprising a plurality of similar layers, each of said layers consisting of spaced diamonds embedded in a sintered hard metal carbide matrix impregnated with a cupreous metal, the number of diamonds in each layer beingsubstantiallyequal and spaced apart substantially equal distances.

2. A diamond tool comprising a plurality of similar and substantially parallel dome shaped layserted in the opening 2 of the mold and a diamond placed in each of the openings in the loading plunger and pressed into position in the carbide powder by the press rods l3 and I4, after which the loading plunger 9 is withdrawn and the diaers, each of said layers consisting of diamonds embedded in a sintered matrix, said matric con- -)sisting of one or more hard metal carbides immonds again covered with carbide powder which is again provided with the desired dome shaped surface.

In the manufacture of'truing tools I generally employ above five domed shaped layers of diamonds embedded in carbide powder, the diamonds in each layer being spaced apart exactly the same distance and the successive layers being so positioned that as the diamonds in one layer wear out the next succeeding series or layer is in an operative position. :Each layer has substantially the identicalcontour and spacing of diamonds as the first or bottom layer- When the desired numberof layers of carbide powder and diamonds have been formed addi tionalpowdered carbide is added to form the bottom or shank portion of this tool and provide the desired length of tool.- Pressure is then applied to this additional carbide powder by the top plunger I! to form a flat base on the tool. The compressed tool nowmay be removed from mold I and plunger 4 and heated in any convenient manner to a temperatureof about 650 C.

U ,The presintered tool which has the appearance and 'sizeof the tool 18 illustrated in Fig. 11 is rigid enough to'"be handled without breakage and is now inserted in a graphite receptacle 19, the diamond end of the tool being uppermost in the mold. The tool fits loosely within the mold and is surrounded by copper or, a cupreous alloy 29 which may be in the form of powder or filings, or sheet metal. The graphite receptacle and material therein are now heated at a temperature of about 1150 to 1200 C. to further sinter the carbidematrix, melt the copper, and cause it to impregnate the pores in the carbide matrix.

In my improved truing tool the diamonds in each layer are spacedapart substantially equally in a predetermined manner and each dome shaped arrangement of diamond is substantially identical in shape and cutting ability with the others. Itis possible therefore to provide tools of uniform quality. The cupreous impregnating metal assists in providing astrong matrix in which the .diamonds are rigidly held in position. A further advantage of the present process is its adaptability to mass production methods since the various operations obviously are adapted to be carried out in successive steps.

'pregnated with a cupreous metal.

3. A diamond tool comprising a plurality of similar, substantially parallel dome shaped layers,

each of said layers consisting of diamonds embedded in a sintered matrix consisting of one or more carbides from the group tungsten carbide, molybdenum carbide, tantalum carbide and titanium carbide impregnated with copper.

4. The method of making a diamond tool which comprises positioning diamonds in cavities on a concave surface covering the upper portion of said diamonds with a powdered matrix, forming a dome shaped surface on said powdered matrix substantially parallel to said concave surface, partially embedding a series of diamonds in said suriace,- covering said diamonds with a powdered matrix, pressing a concave surface on said matrix and adding diamonds and powdered material as before to provide a desired series of substantially parallel-dome shaped layers each consisting of spaced diamonds and a powdered matrixthereior and thereafter sintering said matrix and impregnating it with a cupreous metal.

GEORGE W. LUCAS.

REFERENCES orrEn The following references are of record in the file of this patent:

*fUNI'rED STATES PATENTS Number Name Date Re. 22,373 Benner et a1 Sept. 14, 1943 1,587,805 Taylor June 8, 1926 1,904,568 Taylor 1 Apr. 18, 1933 1,996,598 Taylor Apr. 2, 1935 2,068,848 De,Bats -J an. 26, 1937 2,141,202 Wallace Dec. 27, 1938 2,170,164 Stone et al. Aug. 22, 1939 2,182,562 Koebe1 Dec. 5, 1939 2,200,281 Koebel May 14, 1940 2,228,871 De Bats Jan. 14, 1941 2,339,270 Kelleher 1 Jan. 18, 1944 2,349,825 Kelleher May 30, 1944 2,358,459 Kelleher Sept. 19, 1944 FOREIGN PATENTS Number Country Date 16,881 3 Great; Britain July 16, 1897 543,633 Great Britain Mar. 5, 1942 101,940 Sweden Apr. 30, 1941 110,118

Australia Mar. 13, 1940 

